Sheet separating device for photocopying machines



June 4, 1968 A. M. HYOSAKA 3,386,730

SHEET SEPARATING DEVICE FOR PHOTOCOPYING MACHINES Filed Oct. 14, 1966 FIG! INVENTOR: ALFRED M. HYOSAKA AIT'YS United States Patent O "we 3,386,730 SHEET SEPARATING DEVICE FOR PHOTOCOPYING MACHINES Alfred M. Hyosaka, Chicago, Ill., assignor to Speed-()- Print Business Machines Corporation, Chicago, 111., a corporation of Illinois Filed Oct. 14, 1966, Ser. No. 591,368

7 Claims. (Cl. 271-64) This invention relates in genera-l to photocopy machines. The invention is designed as an improvement over the particular apparatus for separating sheets passing through a photocopy machine as disclosed in my earlier filed copending application Ser. No. 543,648 filed Apr. 19, 1966. Still more specifically, the invention is directed to a novel cross-sectional configuration of the filaments used in the sheet separator.

The invention is particularly applicable to and useful in photocopy machines which carry out the electrostatic process of copying images from an original document onto a copy sheet. In my aforesaid copending application a device has been illustrated wherein the image-bearing original and the copy sheet are inserted into the machine and conveyed therethrough in a manner such that the copy sheet is exposed to an electrostatic discharge device. The particular machine illustrated discloses the imagebearing original as being passed around the discharge device, although as far as the sheet separating device is concerned, it is immaterial whether the copy sheet only or both sheets pass through the dis-charge zone.

After the original document has been charged on the photoconductor-coated surface thereof, the original is brought into contact therewith and both sheets pass through an exposure zone. As is well known in this process, light which passes through the original onto the charged surface of the copy sheet dissipates the charge in the non-image areas and thereafter when the copy sheet is passed through a toner, the charged areas which correspond with the image areas on the original attract the toner particles and thereby reproduce the original image.

My aforesaid copending application is directed primarily to a sheet separating device which includes a plurality of relatively thin elongated filaments disposed in diverging relation in the direction of movement of the two sheets. The original sheet is in contact with one set of [filaments while the copy sheet is in contact with the other set of filaments. As the two sheets move through the machine past the exposure zone or station, they will move in diverging paths due to the positions of the filaments and thereby become separatedwAt this point in the operation of the device, the original is conveyed out of the machine while the copy sheet is conveyed through an area where a toner is applied, such as a liquid toner, and thence outwardly of the machine.

It has been ascertained that commercially available filaments, when used in the aforesaid combination, tend to create fine lines or shadows on the copy sheet due to the fact that light from the exposure lamp does not reach the copy sheet in the area where the filaments are present.

While the presence of such line shadows on the copy sheet does not impair the reproduction of the original, it may nevertheless detract somewhat from the ultimately desired perfectly clean copy.

Commercially available filaments, such for example as a nylon monofilament or a polyester monofilament, are substantially circular in cross-sectional configuration. It has been determined that if the cross-sectional configuration of these sheet separating filaments is modified so that the width of the surface thereof in contact with the sheet curves away from the sheet rather sharply, the resulting very fine line in contact with the sheet will not create a 3,386,730 Patented June 4, 1968 shadow. Furthermore, if the filament surface curves away from the sheet rather rapidly as compared with that of a circular filament, insufficient light from the exposure lamp is prevented from reaching the copy sheet to create shadows. As a result, a clean copy is produced without the presence of any line shadows which are discernable to the naked eye.

In view of the foregoing, it is a principal object of the present invention to provide a filament for use in a sheet separating unit for a photocopy machine wherein the cross-sectional configuration thereof is non-circular.

Another object of the invention is to provide a nylon or polyester monofilament having an elongated cross-sectional configuration so that when the filament is used in a photocopy machine to separate sheets moving therethrough and positioned between the sheets so that the surfaces thercof having the smaller dimension are in contact with the sheets, shadows on the copy sheet due to the presence of the filaments will be eliminated.

-A further object of the invention is to provide a filamerit for use in a photocopy machine for separating the original and copy sheets passing therethrough wherein the cross-sectional configuration thereof is elongated with the width thereof having a dimension within the range of from .002 inch to .010 inch and with the cross-sectional length thereof within the range of .005 inch to .125 inch.

A still further object of the invention is to provide a sheet separating unit adapted for use in a copying machine for separating sheets moving therethrough, wherein use is made of a plurality of filaments extending in the direction of movement of the sheets and positioned in diverging relation to separate the sheets, and wherein each of the filaments has an elongated cross-sectional configuration with relatively sharp curved surfaces in contact with the sheets, whereby to substantially eliminate line shadows on the resulting copy.

Still another object of the invention is to provide in combination with a photocopy machine, sheet separating means for separating the original and copy sheets passing therethro-ugh after exposure thereof, wherein the sheet separating means is comprised of a plurality of spaced-apart relatively thin filaments each having an elongated cross-sectional configuration and wherein said filaments are located between the sheets and extend in diverging relation in the direction of movement of the sheets and positioned so that in the area of the exposure station the surfaces thereof having the smaller dimension are in contact with said sheets.

Other objects and advantages of the invention will become apparent upon reading the following description taken in conjunction with the accompanying drawing, in which FIG. 1 is a perspective view of the sheet separator unit as used in the photocopy machine illustrated in my aforesaid copending application illustrating the manner in which the original and copy sheet are separated by the thin filaments therein;

FIG. 2 is an end elevational view of a preferred form of the sheet separator unit shown in FIG. 1;

FIG. 3 is an enlarged cross-sectional view through one of the filaments of the present invention, and

FIG. 4 is a view similar to FIG. 3 but showing a modified form of cross-sectional configuration.

Referring now more particularly to the drawings, FIG. 1 illustrates the environment of the invention. My above referred to copending application discloses a machine wherein the original and the copy sheet pass through the machine, the copy sheet being exposed to an electrostatic discharge and then being brought into contact with the original adjacent the area or zone where the exposure to light takes place.

In FIG. 1 the image-bearing original sheet is indicated by the numeral 1 and the copy sheet is indicated by the numeral 2. In this instance the copy sheet has its photoconductor-coating on the underside thereof. The roller 3 is preferably transparent and has positioned therein a suitable light source. One or more rollers 4 are positioned below the roller 3 and these rollers cooperate to feed the two sheets through the exposure area and along the sheet separating assembly.

While any suitable means may be provided to support the filaments having the novel cross-sectional configuration of the present invention, the illustrated embodiment herein includes a frame generally indicated by the numeral 5 which preferably has a generally rectangular configuration. This frame is provided with a generally rectangular opening 6 therein. The ends 7 and 8 of the frame 5 may be substantially flat while the forward edge of the frame is provided with an upwardly extending flange 9. The rearmost edge of the frame is illustrated as being bent upwardly and rearwardly, as at 10, on an inclined plane.

The sheet separator unit then includes the plurality of very thin filaments which span the opening 6. These are preferably nylon or polyester monofilaments. Some of these filaments are directed upwardly and others are positioned therebelow in forwardly diverging relationship to those extending upwardly. The image-bearing original 1 will be directed to the upper surface of the uppermost filaments and the copy sheet will be directed to the underside of the lowermost filaments, and as the two sheets continue to move forwardly, the two sets of filaments will separate them.

In the drawing, the plurality of upwardly directed filaments are indicated by the numeral 11 while the lowermost filaments are indicated by the numeral 12. It will be apparent that the number of filaments used in both the upper and lower reaches are not particularly critical except for the fact that there should be at least one lower filament and at least two upper filaments.

The manner in which this separator unit is mounted within the machine housing is described in greater detail in my aforesaid copending application, although the manner of mounting does not form a part of the present invention.

As the image-bearing original passes through the machine and is directed downwardly toward the separator unit, the leading edge thereof will come against the upper surface of the upper filaments 11. The copy sheet, as it emerges from the discharge unit, will enter the opening 6 at the rear thereof below the lowermost filaments 12. Both sheets will reach the bite of the rollers and will be fed forwardly from that point. The exposure takes place when the original and copy sheets are in surface-tosurface contact with each other, with the upper and lower filaments 11 and 12 therebetween. As the two sheets continue to move through the machine after exposure, the original will ride upwardly along the filaments 11 and will be directed to a passageway which directs it out of the machine. As the copy sheet continues to move through the machine, the one or more lower filaments 12 will prevent the copy sheet from clinging to and moving upwardly with the original sheet which it normally has a tendency to do because of the charge thereon.

Thus, the copy sheet 2 must stay underneath the lowermost filament or filaments 12, and the leading edge thereof will contact a deflector which deflects the sheet downwardly where it is fed by additional rollers downwardly into and through an area where a toner is applied thereto.

As stated hereinbefore, the nature of the electrostatic copying process is such that light pases through the image-bearing original in the non-image areas thereof and dissipates the previously applied charge from the copy sheet in the areas corresponding to the non-image areas of the original. This leaves on the copy sheet a latent V 4 image which is later made visible by application of toner t "iereto.

The presence of the separating filaments between the two sheets, unless the size and shape thereof are properly designed, will preveht some of the light from reaching the copy sheet in the areas where the filaments are present. This results in very fine line on the copy sheet where the charge has not been dissipated, whereupon the image of the filament will appear on the copy.

The normal and usual filament which has heretofore been used for the purpose herein described has been substantially circular in cross-sectional configuration and even though the diameter thereof is reduced to as small as practically possible, a very fine line still appears on the copy, which line was not on the original.

It has been found that when the cross-sectional configuration of the filaments, at least in the area of the exposure zone, is elongated and positioned between the two sheets so that the surface of smaller dimension is in contact with the sheets, then the line images are eliminated, or at least diminished to the point where they are hardly visible with the naked eye.

This is especially true where the surfaces of smaller dimension are arcuate. In this case the light passes through the original in the non-image areas and will also pass through on the opposite sides of the very minute area where the filament is in contact with the sheet.

FIGS. 3 and 4 illustrate forms of the invention which are preferable. In FIG. 3 the cross section of the filament 11 is elongated and has substantially parallel sides 13. The ends are arcuate. For example, the upper end 14 is arcuate so that the area thereof in contact with the upper or original sheet 1 is as small as possible. Likewise, the lower end 15 which contacts the lower copy sheet 2 is arcuate for the same reason. It will be noted from the point of contact between the sheet and the surface of the filament, the arcuate surface curves away from the sheet rather rapidly, whereby all but a very minute part of the light will pass through the non-image areas of the original and onto the charged surface of the copy sheet.

The wider the cross section of the filament, the greater are the chances for a line or shadow to appear on the copy. It is thus desirable to have this dimension of the filament as small as possible. On the other hand, for practical reasons it cannot be made too small and yet function properly and it has, therefore, been determined that the width of the filament should not be less than .002 inch nor should it be greater than .010 inch. When it is greater than this dimension, shadows may appear visible to the eye on the copy sheet.

Likewise, since the two sheets are in surface-to-surface contact except where the filaments separate them, it is desirable to have the length of the cross section as small as possible. In this connection it has been determined that for practical reasons the lengthwise dimension of the cross section of the filament should not be less than .005 inch nor should it be greater than .125 inch.

FIG. 4 illustrates a modified cross-sectional configuration wherein the sides of the elongated cross section are also arcuate together with the ends thereof. For example, in FIG. 4 the filament 11 has the sides 16 thereof arcuate on a relatively large radius, whereby the ends 17 and 18 thereof are curved on a relatively short radius. The dimensions of the width and length of the cross section, however, should remain within the same tolerances above mentioned with respect to the form shown in FIG. 3. That is to say, the length of the filament should remain within the range of about .005 inch to .125 inch, while the width thereof should remain within the range of from about .002 inch to .010 inch.

Within these respective ranges, of course, it will be understood that as the width increases, the length must also increase proportionately so that the cross-sectional configuration at all times will be elongated and positioned between the sheets, at least in the exposure zone, so that the ends of lesser dimension will be in contact with the sheets. By the use of this invention it has been determined that excellent copies may be obtained without the appearance of any lines or shadows thereon due to the presence of the separating filaments which can be visible or noticeable to the eye.

Changes may be made in the form, construction and arrangement of parts from those disclosed herein without in any way departing from the spirit of the invention or sacrificing any of the attendant advantages thereof, provided, however, that such changes fall within the scope of the claims appended hereto.

The invention is hereby claimed as follows:

1. The combination with a photocopy machine wherein an image-bearing original sheet and a charged photoconductor-coated copy sheet move past an exposure station in surface-to-surface contact, of sheet separating means for separating said original and copy sheets after exposure thereof, said means comprising a plurality of spaced-apart relatively thin filaments each having an elongated cross-sectional configuration located between said sheets at the exposure station and extending generally in the direction of movement of said sheets, at least one of said filaments being positioned in diverging relation with respect to the others of said filaments, said filaments being so positioned in the area of the exposure station that the surfaces thereof having the smaller dimension are in contact with said sheets.

2. The combination of elements as defined in claim 1 wherein the surfaces of said filaments in contact with said sheets are arcuate. v

3. The combination of elements as defined in claim 1 wherein the cross-sectional length of each said filament is within the range of from .005 inch to .125 inch.

4. The combination of elements as defined in claim 1 wherein the cross-sectional width of each said filament is within the range of from .002 inch to .010 inch.

5. The combination of elements as defined in claim 1 wherein the cross-sectional length of each said filament is within the range of from .005 inch to .125 inch, and the cross-sectional width of each said filament is within the range of from .002 inch to .010 inch.

6. A sheet separating unit adapted for use in a copying machine for separating sheets moving therethrough comprising, a frame having a generally rectangular opening therein, and a plurality of relatively thin filaments extending across said opening in spaced apart relation, at least one of said filaments being positioned in diverging relation with respect to the others of said filaments, whereby two sheets passing through the machine in a substantially horizontal plane, one in contact with the lower surface of said one filament and the other sheet in contact with the upper surface of the remaining filaments, will be caused to move in diverging paths and become separated, each of said filaments having an elongated cross-sectional configuration and being so positioned in said frame that the greater cross-sectional dimension thereof extends transversely to the planes of said sheets, whereby the surfaces thereof having the smaller dimension are in contact with said sheets.

7. The combination of elements defined in claim 6 wherein the surfaces of said filaments in contact with said sheets are arcuate.

References Cited UNITED STATES PATENTS 3,069,990 12/1962 Eisbein et al 9575 3,251,729 5/1966 Shaw 264167 X EVON C. BLUNK, Primary Examiner.

R. J. HICKEY, Assistant Examiner. 

1. THE COMBINATION WITH A PHOTOCOPY MACHINE WHEREIN AN IMAGE-BEARING ORIGINAL SHEET AND A CHARGED PHOTOCONDUCTOR-COATED COPY SHEET MOVE PAST AN EXPOSURE STATION IN SURFACE-TO-SURFACE CONTACT, OF SHEET SEPARATING MEANS FOR SEPARATING SAID ORIGINAL AND COPY SHEETS AFTER EXPOSURE THEREOF, SAID MEANS COMPRISING A PLURALITY OF SPACED-APART RELATIVELY THIN FILAMENTS EACH HAVING AN ELONGATED CROSS-SECTIONAL CONFIGURATION LOCATED BETWEEN SAID SHEETS AT THE EXPOSURE STATION AND EXTENDING GENERALLY IN THE DIRECTION OF MOVEMENT OF SAID SHEETS, AT LEAST ONE OF SAID FILAMENTS BEING POSITIONED IN DIVERGING RELATION WITH RESPECT TO THE OTHERS OF SAID FILAMENTS, SAID FILAMENTS BEING SO POSITIONED IN THE AREA OF THE EXPOSURE STATION THAT THE SURFACES THEREOF HAVING THE SMALLER DIMENSION ARE IN CONTACT WITH SAID SHEETS. 